1. Field of the Invention
The present invention relates in general to a plasma display panel (PDP), and more particularly, to an alignment structure for assembling a plasma display panel.
2. Description of the Related Art
Recently, a variety of flat panel displays, such as liquid crystal display (LCD) and plasma display panel (PDP) have been intensively developed to replace cathode ray tube (CRT) displays. In PDP technology, ultraviolet light is emitted to excite RBG phosphors and produce visible light. The advantages of the PDP include a large display area, wide viewing angle, and intense brightness.
FIG. 11 illustrates a conventional plasma display panel structure. The PDP comprises a rear glass substrate 300 and a front glass substrate 308 spaced apart from each other. A plurality of address electrodes (data electrodes) 302 is disposed on the rear substrate 300 and faces the front substrate 308. A dielectric layer 304 is provided overlying the rear substrate 300 to cover the address electrodes 302. Moreover, a plurality of rectangular or hexagonal rib structures 306 adjacent to each other is disposed on the dielectric layer 304 to define discharge cells. Phosphors (not shown) having three primary colors (R, G, and B) are alternately coated on the discharge cells defined by the rib structures 306. A plurality of pairs of display electrodes (scan electrodes) 310 is disposed on the front substrate 308 and faces the rear substrate 300. Each pair of display electrodes 310 comprises a transparent electrode 310a and a bus electrode 310b. A dielectric layer 312 and an MgO protective layer 314 are successively provided on the display electrodes 310. An inert gas, such as argon, is injected into the discharge cells after the rear and front substrates 300 and 308 are sealed.
For luminance efficiency and quality assurance, it is necessary that the display electrodes on the front substrate be accurately aligned with the discharge cells defined by the rib structures on the rear substrate. In general, alignment marks with a circular or cross shape are additionally formed on the front and rear substrates, respectively. However, an alignment mark with a circular or cross shape on the rear substrate is formed when the address electrode is formed. The alignment mark must undergo several thermal processes for the fabrication of dielectric layer and rib structures. As a result, the alignment mark deforms or shifts from the original position, significantly increasing alignment errors.